Like many of the games released within the middle of a generation, Pokémon Black 2 & White 2 have provided a variety of changed to the breeding mechanics. These changes help you to be able to fully get Pokémon you want from the eggs. These changes predominantly focus upon the creation of the Egg, with the natures and abilities you desire. However, there are also some helpful changes to how to hatch eggs. Unlike in most games, in Black 2 & White 2, you are unable to breed Pokémon until you have defeated the Elite Four and made it to Route 3.

Nature Mechanics

Back in Pokémon Emerald, the new feature was introduced that allowed for you to transfer the nature of one of the parent Pokémon. It started off with it being just the mother holding it, but from HeartGold & SoulSilver onwards, it changed to allow for either parents to do it. This was a 50% chance of passing it down. In Pokémon Black 2 & White 2, however, it has been changed once again. Now, when a parent Pokémon holds the Everstone, the baby Pokémon is guaranteed to hatch with the nature of the Pokémon holding the Everstone. If both parents are holding an Everstone, it is split so each nature has a 50% chance of being passed down.

Ability Mechanics

Since abilities were introduced in Ruby & Sapphire, when a Pokémon breeds, the baby Pokémon, if it is capable of having two abilities, has a 50% chance of getting either of the abilities. Black 2 & White 2 has changed this. Now, the ability the Pokémon will hatch with is dependant upon the mother. If the mother has their ability in slot 1, then the baby has an 80% chance of hatching with that ability, and 20% for the second ability and viceversa if the mother has the ability in the second slot. This calculation even happens if the baby Pokémon, or the mother, only has one ability, since the ability is the same in both slots. For example, if you are breeding a female Pidgeot and it has the ability of Tangled Feet, the baby Pidgey will have an 80% chance of having the ability Tangled Feet and a 20% chance of having Keen Eye. However, this does not mean the baby will inherit the exact ability. For example, Venonat has Compoundeyes in Slot 1 and Tinted Lens in Slot 2 while Venomoth has Shield Dust in Slot 1 and Tinted Lens in Slot 2. If you breed the Venomoth with Shield Dust, then the baby Venonat has an 80% chance of having Compoundeyes
The abilities listed in our Pokédex match the ability order so can be used for reference

Like in Black & White, if the mother has got their Hidden Ability and the father does not, the baby Pokémon has a 60% chance of hatching with its Hidden Ability, with a 20% chance for each of the other possibile abilities that it can have.

If Ditto is used in either of these, either as the female or the male, then the baby Pokémon will only have its standard abilities, with a 50% chance of being in either slot.

Hatching Mechanics

Hatching Pokémon has always been a bit of a chore, having to hatch Pokémon solely by moving around the region. In Emerald, Pokémon with Magma Armor or Flame Body as their abilities halved the amount of steps required if they're in your party while in Black & White, Hatching Power was introduced as a Pass Power which halves the amount of steps needed during any length of time. Black 2 & White 2 have pushed this even further. As you get your Join Avenue to Level 15 and have defeated the Elite Four, you will encounter people who can open up Nursery shops. These nurseries can sell a variety of special items which affect egg hatching.

These items can only be purchased one each a day, but can dramatically cut the amount of steps required to hatch the egg. If it takes the eggs to zero, the egg will hatch as you move away from the store. The items are as follows

Name

Store

Effect

Incubating Lv1

Nursery

You slowly incubate an egg. It becomes a tiny bit faster. - Increases by 5%

Incubating Lv2

Nursery

You slowly incubate an egg. It becomes a little bit faster. - Increases by 30%

Incubating Lv3

Nursery

You slowly incubate an egg. It becomes quite a bit faster. - Decreases steps by 5,120

Incubating Lv4

Nursery

You slowly incubate an egg. You can speedup most eggs. - Decreases steps by 7,680

Incubating Lv5

Nursery

You slowly incubate an egg. You can speed up all eggs. - Decreases steps by 10,240